In a liquid crystal device defined as an electro-optic device used in an electronic device such as a projector, for example, light is incident on one surface of the liquid crystal device. Light characteristics of the incident light are spatially modulated by driving a thin-film transistor that electrically controls optical transparency of the liquid crystal device and then applying a potential to a liquid crystal region. The light is then made to emerge from the other surface of the liquid crystal device such that patterns of images or letters are formed. Herein, to minimize a light leakage current caused by the incidence of the light on a channel region of the thin-film transistor, such a structure is employed, that a light-shielding layer is formed between the thin-film transistor and a light source of the light.
Other than the above case, the light having been incident on one surface sometimes returns to a channel part of the thin-film transistor due to, for example, reflection on the other surface of an electro-optic substrate. To prevent the light described above from being incident on the thin-film transistor, the employed structure is that another light-shielding layer is formed between the thin-film transistor and a second surface of the electro-optic substrate. This light-shielding layer prevents the light from being directly incident on a semiconductor layer of the thin-film transistor.
In recent years, SOI technologies have been considered in accordance with reduction of writing time per pixel, request for high contrast, and soon, that results from increase in pixel number of a display device. With the use of the SOI technology, a thin-film transistor of a single crystal can be used instead of a thin-film crystal of a polycrystal, thereby achieving high-speed switching. Patent Document 1, for example, describes a manufacturing method by which a light-shielding layer at a closer side to a substrate is obtained using the SOI technologies. By this manufacturing method, the light-shielding layer is formed on a surface of an optically-transparent substrate, thereby being covered with a silicon oxide film, which is then flattened by polishing. A single-crystal silicon film is then affixed onto the flattened surface. Thereafter, the single-crystal silicon film is eliminated while a thin-layer of a single-crystal silicon is left. In this manner, a substrate having an SOI is formed.
[Patent Document 1]
Japanese Unexamined Patent Application Publication No. 10-293320